Comment by Twey

Well, `foldr` is (up to interdefinability) just the implementation of `for_` (or `traverse`) in the case of lists, in the same way that `map` is the implementation of `fmap`. The point of `traverse` is that it's provided by the functor.

The question of whether to use the most generic (for consistency) or the least generic (for directness) name for a function is the old bugbear of the Prelude :)